Carburetor



Mmhzs, 41937.

\ s. F. HUNT 2,074,729

CRBURETOR Filed Jan. l`6, 1933 IN VEN TOR.

. 5m# E Hum Patented Mar. 23, 1937 V `uNlTlzl) sTATlzs PATENT ol-"FlceCARBURETOB Scott F. Hunt, Detroit, Mich., assignor to Bendix AviationCorporation, South Bend, Ind., a corporation of Delawarenpplieauonuanuary 16, 1933, serial Nassau `4 claims. (ci. 12a- 119i Thisinvention relates to carburetors, more es- Figures 3 and 4 `are viewssimilar to Figure2 pecially to automatic choke valve control mecha# butshowing modified forms of the invention; `nisms therefor, and has forits principal object and i l the provision of an improved thermostatcontrol Figure 5 is a detaiiview of a spacing collar. 5 for amechanismof this kind. i l l Referring now to the drawing in more detail, 5Internal combustion engines using liquid fuel Vthe carburetor ill is adown draft plain` tube carrequire a richer mixture when the engine iscold i buretor having a choke valve i2 located in the air than when itis hot. Carburetors for forming l intake horn I3, and a throttle Ilcontrolling the this fuel mixturev are provided with a control mixingchamberli. The casing is flanged at i6 l valve, usually an `air supplyregulating valve or to facilitate mounting the carburetor on the in- 10l choke, which is adjustable to regulate the richtake manifold i1 of theengine. The choke valve ness of the mixture. Certain prior art devices,of control mechanism, indicated generally at 20, which the copendingapplication of S. F. Hunt, is iixed upon the manifold adjacent tothercar- `Serial No. 653,518, filed January 25, 1933, is an buretor.` Itis to be understood that the specific l example, provide a controlmechanism for addiarrangement shown is shown by way of example 15 `tionto or incorporation in the carburetor to autoonly as the invention maybe applied to other maticaily control the choke valve to produce a typesof carburetors and the control mechanism mixture varying in richnessinversely as the enmay be incorporated in the carburetor structure, l hgine temperature. Thiscontrol is regulated by a within the` teachings ofthe present invention. thermo-stat which is usually mounted in juxta-The choke valve I2 is mounted by a Shaft 22 20 position to the exhaustmanifold of the i engine which carries a lever 24 through which thechoke and heated thereby. The automatic control deis moved. Thefreeendof the lever 24 carries a vice may be locked in operated positionwhen the' rod 26, pvtally `Sllled thereto, and the other `engine is atnormal operating temperature, so end of this rod is pivoted to a. lever28 `that is that the mixture then delivered to the engine is fixed upona thermostat shaft 30. `The choke 25 regulated by the carburetoradjustments rather valve I2 is of the unbalanced type, that is to say,than by the choke valve, f `pressure `,difference between its facestends to In certain instances the thermostat will be open the valve.This movement. of the valve is heated too rapidly by heat radiateddirectly from opposed by the Ytension of the thermostat 32, 30 themanifold when the engine isy started,` with which tension decreases asthe temperature in- 30 the result that the richness of the mixture willCTBRSGS- The throttle lever lllmay, if desired. be be graded down toorapidly. The exhaust manioonoeotedrto the control unit 20 by a rod 33,fold, being composed of relatively thin metal, .as 'disclosed in theHunt application above recools down rapidly and the thermostat may alsoferred to. h cool down too rapidly when the `engine is stopped` Thethermostat 32 is fixed at one end to the 35 or run at idling speed, withthe result that, when `shaft 3U and at the other endto a casing 34 bythe engine is restarted before it has had time to pin 35- The Casing 34iS 013911 faced and is get cold or is brought up to a high speed aftermounted concentrically of the shaft 30 on a boss idling, the mixturedelivered `to it will be too rich. 3B which proieots from the housingofthe con 40 The present invention teaches improving the `trol unit 20.The casing 34 is rotatable upon the 40 operation of the prior artdevices by absorbing boss to adjust the tension of the thermostat, and aquantity of heat from the manifold during the is held in place by asuitable clamp and screw warming up period of the engine and dissipatingindicated at l0. l

that heat during the cooling down period to alter The control mechanismis located so as to the operations of the thermostat, and provides bringthe Openrface 0f the (5851118 u Opposite 45 `means for accomplishingthis result. the exhaust manifold 42, but at some distance My inventionwill be best understood from the therefrom. The intervening space isfilled by accompanying detailed descriptionof axpreferred a heatabsorbing medium 44 shown as a block embodiment of it, reference beinghad to the of metal secured to the manifold by bolts 46.

accompanying drawing in which: A soft metal gasket 48, preferablycopper, is in- Figure l is an elevational view of a carburetor terposedbetween the block M and the manifold, and control mechanism therefor;and as the bolts are drawn up tight, the soft Figure 2 is an endelevational view of Figure-l, gasket will be forced into theirregularities of partly in section along the line 2--2 of Figure 1, thesurfaces with which it is in contact to form looking in the direction ofthe arrows; a good heat conducting connection between the 55 of theblock M and serves with it thermostat. The block u is preiquantlty o!heat.

In the operation o! the device, hot gases pass- 42 heat the is restartedbefore it has d a chance to cool down to atmospheric temperature, thethermostat will be above atmospheric temperatureand the mixture will bemaintained at more nearly correct richness. By properly proportioningthe of the thermothe material from which the The gasket 48, specified asa heat insulation between the thermostat.

tion and convection.

In the modiilcation shown in Figures 4 and 5, somewhat the same type ofheat reservoir is4 tions may be made.

I claim:

2. The combination with an internal combustion engine having

